Poligoane

import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;


public class Ascultator  implements MouseListener{

Interfata i;
private Point[] puncte = new Point[50];
private Integer contor = 0;

public Ascultator(Interfata x){
this.i = x;
}

@Override
public void mousePressed(MouseEvent e) {

}
@Override
public void mouseClicked(MouseEvent e) {

++contor;
this.puncte[contor]=e.getPoint();
System.out.println("Coordonatele punctului  "+ contor + " " +this.puncte[contor].x  +" "+this.puncte[contor].y);

if(this.contor % 3 == 0){
System.out.println("Am ajuns la 3 elemente desenam un poligon");

this.i.getP().validate();
this.i.getP().repaint();


}

}

@Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub

}
public Point[] getPuncte() {
return puncte;
}

public void setPuncte(Point[] puncte) {
this.puncte = puncte;
}

public Integer getContor() {
return contor;
}

public void setContor(Integer contor) {
this.contor = contor;
}

@Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub

}
@Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub

}


}

import java.awt.Dimension;

import javax.swing.JFrame;

public class Interfata extends JFrame {

private Ascultator asc = new Ascultator(this);

private Plansa p= new Plansa(asc);

public Plansa getP() {

return p;

}

public void setP(Plansa p) {

this.p = p;

}

public Interfata(){

this.setVisible(true);

this.setSize(new Dimension(250,250));

this.getContentPane().add(p);

this.setDefaultCloseOperation(EXIT_ON_CLOSE);

p.addMouseListener(asc);

}

}

import java.awt.Canvas;

import java.awt.Color;

import java.awt.Component;

import java.awt.Dimension;

import java.awt.Graphics;

import java.awt.Point;

public class Plansa  extends Canvas{

private Ascultator a;

public Plansa(Ascultator a){

this.a= a;

this.setBackground(Color.white);

this.setSize(new Dimension(150,150));

}

public void update(Graphics g){

paint(g);

}

public void paint(Graphics g){

g.setColor(Color.black);

try{

if(this.a.getContor() %3 == 0 && this.a.getContor() != 0 ){

g.drawLine(this.a.getPuncte()[a.getContor()-1].x,this.a.getPuncte()[this.a.getContor()-1].y,this.a.getPuncte()[a.getContor()].x,this.a.getPuncte()[this.a.getContor()].y);

g.drawLine(this.a.getPuncte()[a.getContor()-2].x,this.a.getPuncte()[this.a.getContor()-2].y,this.a.getPuncte()[a.getContor()].x,this.a.getPuncte()[this.a.getContor()].y);

g.drawLine(this.a.getPuncte()[a.getContor()-1].x,this.a.getPuncte()[this.a.getContor()-1].y,this.a.getPuncte()[a.getContor()-2].x,this.a.getPuncte()[this.a.getContor()-2].y);

System.out.println("contor" + this.a.getContor());

}

}catch(NullPointerException e){}

}

}

public class Test {

public static void main(String[] args) {

Interfata i = new Interfata();

i.validate();

i.repaint();

}

}